Semiconductor devices are often provided in packages with multiple connected dies, in which circuit elements of the various dies are connected in various ways. For example, a multi-die package may utilize wirebonds from each die to an interposer to provide connection between elements in different dies. While direct electrical connections between circuit elements in different dies are sometimes desirable, in other cases it may be desirable to connect elements from different dies wirelessly (e.g., via inductive coupling, capacitive coupling, or the like). To facilitate wireless communication between circuit elements in different dies, coils can be provided on the dies, such that adjacent dies in a multi-die stack can have proximate coils that communicate wirelessly.
One approach to providing coils for wireless communication involves packaging two dies in a stacked face-to-back arrangement in a semiconductor package, such that the coils on each die are separated by the thickness of the individual die. This approach usually involves thinning the dies sufficiently to decrease the distance between a coil on one die and a corresponding coil on an adjacent die. With this approach, however, the distance between coils is still relatively large because the dies still need to be thick enough to maintain a minimum strength for handling during the manufacturing process. To compensate for this thickness and ensure sufficient data transmission between the dies, the size of the coils tends to be increased, which thereby increases the cost of the dies in the package and requires additional space to be occupied on the die. Additionally, because the dies are thinned, they are relatively weak and more prone to breaking or chipping, thereby decreasing overall manufacturing yield and increasing unnecessary costs. Accordingly, there is a need for other approaches to providing semiconductor devices with coils for wireless communication.